A Tammy Abraham grabbed a hat trick to steer Chelsea into the fifth round of the FA Cup with a 3-1 win over Luton Town.
Kickoff was delayed due to the ground staff clearing the heavy snow of the pitch.
Chelsea opened the scoring after 11 minutes when Abraham converted Werner's low cross. Luton were furious because there appeared to be two balls on the pitch in the build up to the goal but the officials allowed play to continue.
Abraham slotted in from Timo Werner's cut-back before nodding in a second from Reece James' chip. The Championship side got back into the game after 30 minutes when Kepa failed to keep out Jordan Clark's close-range effort.
Jordan Clark scored for the visitors - after an error by keeper Kepa Arrizabalaga- on 30 minutes to keep them in the game.
But Abraham poked home to seal victory before Timo Werner missed a penalty.
The result eases pressure off Chelsea boss Frank Lampard after a run of poor results in the Premier League.
"It's great to score a hat trick and win so comfortably. Luton are a good side," Abraham told the BBC.
"It's always nice to get a win, hopefully we can build off that form now... hopefully we can build on the confidence from here."
Chelsea will face Championship side Barnsley in the fifth round.